Propriedades e autocicatrização do bioconcreto por meio da incorporação de bactérias do gênero Bacillus subtilis encapsuladas em argila expandida

Abstract

Cracks are a very recurrent pathology, and are present in most of the buildings, usually without structural interference, but they must be remedied correctly to avoid the emergence of secondary problems. The need for periodic maintenance to treat these cracks ends up becoming expensive and uses products that can harm the environment during their production, use and disposal. The alternative studied to reduce the need for external interventions in the structure is the use of bioconcrete. The bioconcrete consists of inserting capsules containing bacteria, in this case, Bacillus subtilis, which at the moment of rupture due to the appearance of fissures and contact with water generates calcium carbonate, a cementing material that will fill the cracks. The study was carried out with the aim of identifying the efficiency of the use of Bacillus subtilis in the production of bioconcrete for the self-healing of cracks and increase in the mechanical properties of concrete. In the first stage of the research, studies of literature review and characterization of the materials used for the production of concrete were carried out, being CPV-ARI cement, medium sand, gravel 1 and expanded clay 1506, obtaining the necessary information for the development of concrete traces. Subsequently, the specimens were molded in three different concrete mixes, being the reference mix, expanded clay mix and, finally, the addition of expanded clay with encapsulated bacteria. The samples made were pre- cracked with 70% of their compressive strength at 7 days after concreting and went through the curing process in cycles for 90 days. At the end of this period, fissure healing, compressive strength, elastic modulus and x-ray diffractometry were analyzed. With the analyzed results, it was possible to conclude that the use of bacteria for the production of concrete is efficient for the healing of cracks and increase in the mechanical properties of concrete.